Existing suction pipes for extracting fluid from a liquid transport tank, such as that of fire truck typically comprises a pipe, parallel to the bottom of the tank with a 90° elbow coupled to its interior end and angled down. The right angle bend in the suction pipe disrupts laminar flow of liquid into the pipe, creating resistance and decreasing efficiency.
To allow sufficient clearance, such an elbow is typically positioned over the sediment sump, a required depression and cleaning port located at the lowest point of the tank to allow particulates and debris that might accumulate in the tank to be removed. The positioning of the elbow over the sump, while allowing greater inflow into the suction also results in disturbance of the sediment in the sump and its mixing with the liquid being pumped through the suction. This defeats the purpose of the requirement for a sump.
One way to improve sump performance in such a situation is to make the sump deeper. This too has significant practical disadvantages, notably, a sump that extends more than 3 inches beyond the bottom of the tank may impinge on other structures installed in the truck, requiring extensive reconstruction of tanks to fit trucks from different manufacturers.
What is needed, therefore, are techniques for providing a tank with a low profile sump and high efficiency suction.